A turbine blade near-wall tube array cooling structure

Abstract

The application discloses a turbine blade near-wall pipe array cooling structure and relates to the field of gas turbine turbine blade cooling structures. The turbine blade is a hollow structure, a middle cooling medium cavity in the turbine blade is provided with cooling medium, a plurality of cooling channels are arranged in the wall body of the turbine blade and close to a gas surface, the plurality of cooling channels are arranged in an array form and form a micro pipe array, two adjacent cooling channels are arranged in a positive and negative mode and the medium flow directions are opposite, each cooling channel is a bamboo pole structure which comprises N+1 circular pipes and N rotating flow bamboo joints which are arranged alternately and connected and communicated in sequence, and the rotating flow bamboo joints of two adjacent cooling channels are arranged in a reverse and staggered mode. The application is mainly used for cooling of turbine blades.

Description

Technical Field

[0001] This invention relates to the field of cooling structures for gas turbine blades, and more specifically to a near-wall tube array cooling structure for turbine blades. Background Technology

[0002] In pursuit of high efficiency and high power, gas turbines are constantly increasing turbine inlet temperatures. Currently, the turbine inlet temperature of advanced heavy-duty gas turbines has reached over 1700K, far exceeding the allowable temperature of metallic materials. To ensure the safe operation of the turbine, higher requirements are placed on efficient cooling technology.

[0003] Existing turbine cooling technologies aim to achieve higher cooling efficiency with limited airflow.

[0004] Microchannel arrays are one method to increase heat transfer area. Microchannel structures have been widely used in fields such as microelectronics and bioengineering. By arranging a large number of microchannels within the limited space of the thin-walled turbine blades, the heat transfer area can be effectively increased and the heat transfer performance improved while keeping the total flow rate of the cooling air constant.

[0005] There are various cooling methods to improve the heat transfer coefficient in turbine blades, such as ribbed channels, column rib turbulence, and impact target surface turbulence structures. The principle behind all of these is to increase the heat transfer coefficient by enhancing turbulence. Swirl cooling is also a method to improve the heat transfer coefficient. After cold air enters the swirling chamber, it adheres to the wall surface and generates vortices, increasing the turbulence of the flow, thus increasing the heat transfer coefficient and improving cooling performance.

[0006] With advancements in processing technology, it has become increasingly possible to apply complex, novel cooling structures to turbine blade cooling. This application proposes a novel microchannel structure for use on turbine blades. Summary of the Invention

[0007] To solve the above-mentioned technical problems, this invention provides a near-wall tube array cooling structure for turbine blades. By rationally and densely arranging micro-fine bamboo-shaped cooling channels on the near-wall surface, internal convective heat transfer is enhanced. While effectively increasing the heat transfer area, the swirling bamboo joints increase the turbulence inside the tubes, thereby improving the heat transfer coefficient and thus enhancing the convective heat transfer performance.

[0008] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0009] A near-wall tube array cooling structure for turbine blades, wherein the turbine blades are hollow and a cooling medium is introduced into the central cooling medium cavity in the middle of the turbine blades.

[0010] Several cooling channels are arranged in the wall of the turbine blade near the gas surface. These cooling channels are arranged in an array to form a micro-tube array. Two adjacent cooling channels are arranged in opposite directions and the medium flows in opposite directions.

[0011] Each cooling channel has a bamboo-like structure, which includes N+1 alternating circular pipes and N swirling bamboo sections. The circular pipes and swirling bamboo sections are connected end to end and communicate with each other.

[0012] Preferably, several cooling channels are arranged along the direction from the leading edge to the trailing edge of the turbine blade, and the flow direction of the medium in each cooling channel is the same as or opposite to the flow direction of the medium in the cooling medium cavity in the upper middle part of the turbine blade.

[0013] Preferably, the cooling channel with the same flow direction as the medium in the central cooling medium cavity is a forward cooling channel and has a separate air intake; the cooling channel with the opposite flow direction to the medium in the central cooling medium cavity is a reverse cooling channel, which is connected to the central cooling medium cavity, and the central cooling medium cavity provides cooling medium to the reverse cooling channel.

[0014] Preferably, the cross-sectional shape of the central cooling medium cavity within the turbine blade is the same as the cross-sectional shape of the turbine blade.

[0015] Preferably, the swirling bamboo joint is lantern-shaped.

[0016] Preferably, the swirling bamboo section is shaped like a "truncated cone", and the swirling cavity inside the swirling bamboo section is composed of conical segments and arc-shaped segments arranged coaxially in sequence, with the connection between the conical segments and the arc-shaped segments being tangentially transitioned.

[0017] Preferably, the arc segment in the vortex cavity adopts a constant curvature design, and the center of the arc segment is located on the extension line of the inner wall of the circular pipe. Let the radius of the arc segment be r, the inner diameter of the circular pipe be d, and r / d = 0.3~0.5.

[0018] Preferably, the angle between the wall of the conical segment and the extension line of the circular pipe is α, and the value of α ranges from 30° to 45°.

[0019] Preferably, the swirling bamboo sections between two adjacent cooling channels are arranged in opposite directions and in an alternating manner.

[0020] The beneficial effects of this invention compared to the prior art are:

[0021] 1. This application sets up multiple densely arranged cooling channels in the wall of the turbine blade and forms a micro-tube array, which increases the heat exchange area of ​​the cooling channels, enhances internal convective heat transfer, and improves the cooling effect under limited cooling medium flow.

[0022] 2. This application arranges multiple swirling bamboo sections in the cooling channel. When the low-temperature fluid enters the swirling bamboo section, the fluid flows back along the inner wall of the swirling cavity and generates counterclockwise vortices, which increases the turbulence of the fluid flow, increases the convective heat transfer coefficient, and improves the cooling effect.

[0023] 3. In this application, the two adjacent cooling channels are set in opposite directions of medium flow, and the swirling bamboo joints between the two adjacent cooling channels are arranged in opposite directions and staggered, so that the cooling effect of the wall near the gas surface in the turbine blade is more uniform. Attached Figure Description

[0024] The accompanying drawings, which form part of this application, are provided to further illustrate the invention.

[0025] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0026] Figure 2 for Figure 1 A magnified view of a portion of point A in the middle.

[0027] Figure 3 This is a top view of the present invention.

[0028] Figure 4 for Figure 3 Sectional view at point BB.

[0029] Figure 5 for Figure 4 A magnified view of a section at point C.

[0030] Figure 6 This is a schematic diagram of the structure where the swirling bamboo sections are arranged alternately in two adjacent cooling channels.

[0031] Figure 7 for Figure 6 Sectional view at point DD.

[0032] Figure 8 The diagram shows the flow of cooling medium within the swirling bamboo joint; (a) is a schematic diagram of the flow of fluid within a swirling cavity with a conical surface and an arc surface; (b) is a schematic diagram of the flow of fluid within a swirling cavity with only an arc surface.

[0033] Figure 9 The diagrams show the temperature distribution of the pipe wall and the fluid inside the pipe; (a) is a schematic diagram of the temperature distribution of the pipe wall with a conical and arc-shaped swirling section; (b) is a schematic diagram of the temperature distribution of the fluid inside the pipe with a conical and arc-shaped swirling section; (c) is a schematic diagram of the temperature distribution of the pipe wall with only an arc-shaped swirling cavity; and (d) is a schematic diagram of the temperature distribution of the fluid inside the pipe with only an arc-shaped swirling cavity.

[0034] Explanation of reference numerals in the attached diagram: 1-Cooling channel; 2-Central cooling medium cavity; 11-Circular pipe; 12-Swirl bamboo joint; 121-Conical section; 122-Arc-shaped section. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0036] In order to better achieve the cooling effect of the wall near the gas combustion surface in the turbine blade, this application uses two embodiments for description.

[0037] Example 1:

[0038] See Figure 1 This application provides a near-wall tube array cooling structure for turbine blades. The turbine blades are hollow, and a cooling medium is introduced into the central cooling medium cavity 2 in the middle of the turbine blades.

[0039] Several cooling channels 1 are arranged in the wall of the turbine blade near the gas surface. The cooling channels 1 are arranged in an array to form a micro-tube array. Two adjacent cooling channels 1 are arranged in opposite directions and the medium flows in opposite directions. Each cooling channel 1 has a bamboo pole-shaped structure, which includes N+1 circular pipes 11 and N swirling bamboo sections 12 arranged alternately. The circular pipes 11 and swirling bamboo sections 12 are connected end to end and communicate with each other.

[0040] Furthermore, several cooling channels 1 are arranged along the direction from the leading edge to the trailing edge of the turbine blade. The flow direction of the medium in each cooling channel 1 is the same as or opposite to the flow direction of the medium in the middle cooling medium cavity 2 of the turbine blade. The cooling channel 1 with the same flow direction as the medium in the middle cooling medium cavity 2 is a forward cooling channel and uses a separate air intake. The cooling channel 1 with the opposite flow direction to the medium in the middle cooling medium cavity 2 is a reverse cooling channel and is connected to the middle cooling medium cavity 2. The middle cooling medium cavity 2 provides cooling medium for the reverse cooling channel.

[0041] Furthermore, such as Figure 3 As shown, the cross-sectional shape of the central cooling medium cavity 2 is the same as the cross-sectional shape of the turbine blade.

[0042] Furthermore, such as Figure 8 As shown in (b), the swirling bamboo joint 12 is lantern-shaped.

[0043] In this embodiment, a cooling medium is introduced into the cooling channel 1 of the turbine blade and the central cooling medium cavity 2. The central cooling gas cavity mainly supplies air to the reverse cooling channel. The cooling medium is a low-temperature fluid, which can be a gas or a liquid.

[0044] In this embodiment, the circular pipe 11 is a circular microtube, and multiple cooling channels 1 form a microtube array, which is arranged near the surface of the gas. Under limited cooling medium flow, internal convection heat transfer is enhanced, the heat transfer area of ​​the cooling channels is increased, and the cooling effect is improved. At the same time, two adjacent cooling channels 1 are arranged with opposite medium flow directions, so that the cooling effect of the turbine blade wall near the gas surface is more uniform.

[0045] In this embodiment, a swirling cavity is formed within the swirling bamboo section 12. When the low-temperature fluid enters the swirling bamboo section 12, the fluid impacts the inner wall of the swirling cavity and generates backflow, forming a counterclockwise vortex. This increases the turbulence of the fluid flow, enhances the convective heat transfer coefficient, and improves the cooling effect. The circular pipe 11 and the swirling bamboo section 12 are arranged alternately, and the swirling bamboo sections 12 between adjacent cooling channels 1 are arranged in opposite directions and in a staggered manner. This also makes the cooling effect on the wall near the combustion gas surface in the turbine blades more uniform.

[0046] In this embodiment, the number of swirling bamboo sections 12 is determined by the length of the cooling channel 1 and the heat load. The greater the heat load, the denser the arrangement of the swirling bamboo sections 12. At the same time, the greater the heat load, the closer the micro-tube array is to the gas wall surface of the vortex blades. The number of cooling channels 1 and the distance between two adjacent cooling channels 1 are set according to the volume of the gas side wall and the size of the gas side heat load. The greater the gas side heat load, the more cooling channels 1 there are and the denser their arrangement; conversely, the smaller the gas side heat load, the fewer cooling channels 1 there are and the sparser their arrangement.

[0047] In this embodiment, the cooling medium enters from the medium inlet of the cooling channel 1, flows sequentially through the alternately arranged circular pipes 11 and swirling bamboo sections 12, and exits from the medium outlet of the cooling channel 1; as Figure 8 As shown in (b), when the fluid flows through the swirling bamboo section 12, the fluid will first impact the arc-shaped section of the swirling cavity that is relatively far away, and form a backflow along the arc wall of the arc-shaped section. The backflowing fluid continues to flow along the arc wall (the flow direction of the backflowing fluid is opposite to the direction of the mainstream fluid), and finally merges into the mainstream fluid and flows out of the swirling bamboo section 12. Figure 8 In (b), red represents the high-speed zone and blue represents the low-speed zone.

[0048] Example 2:

[0049] The difference between this embodiment and Embodiment 1 is that the vortex bamboo section 12 is shaped like a "frustum". The vortex cavity inside the vortex bamboo section 12 is composed of a conical section 121 and an arc-shaped section 122 arranged coaxially in sequence, with a tangential transition at the connection between the conical section 121 and the arc-shaped section 122. At the same time, the diameter of the mainstream medium inlet of the conical section 121 is equal to the diameter of the mainstream medium outlet of the circular pipe 11, and the diameter of the mainstream medium outlet of the conical section 121 is equal to the diameter of the mainstream medium inlet of the arc-shaped section 122.

[0050] Furthermore, the swirling bamboo joints 12 between two adjacent cooling channels 1 are arranged in opposite directions and in a staggered manner to ensure a more uniform cooling effect on the wall of the turbine blades near the gas combustion surface.

[0051] Furthermore, the arc segment 122 in the vortex cavity adopts a constant curvature design, and the center of the arc segment 122 is located on the extension line of the inner wall of the circular pipe 11.

[0052] Furthermore, the angle between the wall of the conical segment 121 and the extension line of the circular pipe 11 is α, and the value of α ranges from 30° to 45°, preferably 30°.

[0053] Furthermore, let the inner diameter of the circular pipe 11 be d, and let the distance between two adjacent swirling bamboo sections 12 on each cooling channel 1 be p, p = 5d; let the distance between the central axis of each cooling channel 1 and the wall of the turbine blade near the gas combustion side be h, h = 2d; let the distance between the central axes of two adjacent cooling channels 1 be b, b = 5d, and let the lateral projection distance between the arc-shaped segments of the swirling bamboo sections in adjacent cooling channels 1 be f, f = 3d; let the radius of the arc-shaped segment 122 be r, r / d = 0.3~0.5, and the radius r of the arc-shaped segment 122 is preferably 0.5d.

[0054] In this embodiment, the cooling medium enters from the medium inlet of the cooling channel 1, flows sequentially through the alternately arranged circular pipes 11 and swirling bamboo sections 12, and exits from the medium outlet of the cooling channel 1; as Figure 8 As shown in (a), when the fluid flows through the swirling bamboo joint 12, the fluid will first impact the arc-shaped section 122 of the swirling cavity and form a backflow along the arc wall of the arc-shaped section 122. The backflowing fluid will then continue to flow along the wall of the conical section 121 (the flow direction of the backflowing fluid is opposite to that of the mainstream fluid), and finally merge into the mainstream fluid and flow out of the swirling bamboo joint 12. Figure 8 In (a), red represents the high-speed zone and blue represents the low-speed zone.

[0055] In this embodiment, the design of the inner arc-shaped section 122 of the swirling bamboo joint 12 is to generate a backflow effect, increase the flow turbulence, and thus improve the heat transfer coefficient; while the design of the conical section 121 is to reduce the obstruction of the backflow flow. The inwardly contracting conical surface helps to reduce the low-speed region of the backflow vortex and avoid local high temperatures, such as... Figure 9 As shown in (a) and (b) in the figure.

[0056] Compared with Example 1, Example 2 is as follows: Figure 8 and Figure 9 As shown, the swirling cavity with conical and arc-shaped surfaces in Example 2 has a higher fluid return velocity and less resistance than the swirling cavity with only arc-shaped surfaces in Example 1; and the temperature distribution of the pipe wall and the fluid inside the pipe in Example 2 is more uniform, avoiding local high temperatures.

[0057] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A near-wall tube array cooling structure for turbine blades, characterized in that: The turbine blades are hollow, and the cooling medium is introduced into the central cooling medium cavity (2) in the middle of the turbine blades; Several cooling channels (1) are arranged in the wall of the turbine blade and close to the gas surface. The cooling channels (1) are arranged in an array to form a micro-tube array. Two adjacent cooling channels (1) are arranged in opposite directions and the medium flows in opposite directions. Each cooling channel (1) is a bamboo pole-shaped structure, which includes N+1 alternating circular pipes (11) and N swirling bamboo sections (12), the circular pipes (11) and swirling bamboo sections (12) are connected end to end and communicate with each other; Several cooling channels (1) are arranged along the direction from the leading edge to the trailing edge of the turbine blade. The flow direction of the medium in each cooling channel (1) is the same as or opposite to the flow direction of the medium in the cooling medium cavity (2) in the middle of the turbine blade.

2. The near-wall tube array cooling structure for turbine blades according to claim 1, characterized in that: The cooling channel (1) with the same flow direction as the medium in the middle cooling medium cavity (2) is a forward cooling channel and uses a separate air intake; the cooling channel (1) with the opposite flow direction to the medium in the middle cooling medium cavity (2) is a reverse cooling channel. The reverse cooling channel is connected to the middle cooling medium cavity (2), and the middle cooling medium cavity (2) provides cooling medium for the reverse cooling channel.

3. The near-wall tube array cooling structure for turbine blades according to claim 1, characterized in that: The cross-sectional shape of the central cooling medium cavity (2) inside the turbine blade is the same as the cross-sectional shape of the turbine blade.

4. The near-wall tube array cooling structure for turbine blades according to claim 1, characterized in that: The swirling bamboo joint (12) is in the shape of a "lantern".

5. The near-wall tube array cooling structure for turbine blades according to claim 1, characterized in that: The swirling bamboo section (12) is shaped like a "frustum". The swirling cavity inside the swirling bamboo section (12) is composed of a conical section (121) and an arc-shaped section (122) arranged coaxially in sequence. The connection between the conical section (121) and the arc-shaped section (122) is tangentially transitioned.

6. The near-wall tube array cooling structure for turbine blades according to claim 5, characterized in that: The arc-shaped segment (122) in the swirling cavity adopts a constant curvature design, and the center of the arc-shaped segment (122) is located on the extension line of the inner wall of the circular pipe (11). Let the radius of the arc-shaped segment (122) be... r The inner diameter of the circular pipe (11) is d , r / d =0.3~0.

5.

7. A turbine blade near-wall tube array cooling structure according to claim 6, characterized in that: The angle between the wall of the conical segment (121) and the extension of the circular pipe (11) is . α , α The value range is 30° to 45°.

8. The near-wall tube array cooling structure for turbine blades according to claim 5, characterized in that: The swirling bamboo sections (12) between two adjacent cooling channels (1) are arranged in opposite directions and in an alternating manner.

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